Semi-active robotic joint

ABSTRACT

A robotic joint comprises a first link, a middle link, a torque generator, a second link, and a locking mechanism. Different ends of the middle link are rotatably coupled to the first link and the second link. The torque generator is coupled to the first link and the middle link and is configured to produce torque between these links. The locking mechanism is switchable between a locking state and an unlocking state. In the unlocking state, the locking mechanism allows free rotation of the second link relative to the middle link in the first and second rotation directions. In the locking state, the locking mechanism is configured to impede rotation of the second link relative to the middle link in the first rotation direction and to allow rotation of the second link relative to the middle link in the second rotation direction opposite of the first rotation direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/631,553, filed Jun. 23, 2017, which claims the benefit of U.S.Provisional Patent Application No. 62/354,263, filed Jun. 24, 2016. Bothof these applications are incorporated herein by reference in theirentireties and for all purposes along with all other references cited inthis application.

TECHNICAL FIELD

The apparatus described is an energetically passive exoskeleton knee,configured to be incorporated into an exoskeleton leg.

BACKGROUND

Lower extremity exoskeleton technology has been geared towardsbenefiting medical and augmentation fields. Functional modularity inexoskeleton design allows practitioners to prescribe exoskeletons, whichcan be geared towards the wearer's needs and abilities. While mostmodular knee exoskeleton technology either lives in the realm ofmedicine or augmentation, a stance assistive knee exoskeleton canbenefit both able-bodied individuals as well as individuals withdecreased quadriceps function or knee weakness.

Fully passive systems are lower cost but have limited functionality.Powered systems have diverse functionality but are expensive and large.Microcontroller controlled resistive knees are more functionally diversethan a fully passive system, but only provide system impedance to motionand can be expensive.

Passive microcontroller controlled systems can lead to a low cost andfunctionally versatile system. By embedding some of the requiredfunctionality into the mechanical hardware of the system, the burden onthe microcontrollers and the need for sensors is reduced.

SUMMARY

Several embodiments of energetically passive robotic joints areaddressed here. These energetically passive joints can be used invarious exoskeletons, orthotic systems, prosthetic devices, and roboticwalking machines. These embodiments do not use any external power thatcan be used for locomotion energy, although a battery may be used topower a micro-computer and associated sensors for computation andcontrol. These energetically passive robotic joints, in addition toother behaviors, exhibit two useful characteristics needed to createlocomotion: 1) they can exhibit appropriate resistance in response toflexion when needed while the extension is free at all times even whenthe joint is under the load (e. g. stance phase of an exoskeleton kneejoint); and 2) they can exhibit free flexion and extension when needed(e.g. swing phase of an exoskeleton knee joint). Switching between thesetwo states can provide the fundamental characteristic needed forlocomotion. The basic behavior of these energetically passive roboticjoints is described using abstract forms of electromechanicalcomponents. Then engineered embodiments are described to show how theseenergetically passive robotic joints are designed and built as anartificial knee for exoskeletons, orthotic systems, prosthetic devices,and robotic walking machines. Finally, several embodiments are describedto teach the use of these energetically passive robotic joints forexoskeleton orthotic legs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic representation of an embodiment of theenergetically passive robotic joint.

FIG. 2 is a schematic illustration of an embodiment of the disclosure.

FIG. 3 is a schematic illustration of an energetically passive roboticjoint worn on a person lower limb.

FIG. 4 represents an embodiment of the energetically passive roboticjoint.

FIG. 5 is an exploded view of the embodiment shown in FIG. 4.

FIG. 6 is an exploded view of a portion of the embodiment shown in FIG.4.

FIG. 7 is an exploded view of a portion of the embodiment shown in FIG.4.

FIG. 8 is an exploded view of a portion of the embodiment shown in FIG.4.

FIG. 9 illustrates an embodiment in which the locking mechanism is in alocking state.

FIG. 10 illustrates an embodiment in which the locking mechanism is in alocking state.

FIG. 11 illustrates an embodiment in which the locking mechanism is inan unlocking state.

FIG. 12 illustrates an embodiment in which the locking mechanism is inan unlocking state.

FIG. 13 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 14 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 15 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 16 illustrates an embodiment of the controller state machines.

FIG. 17 illustrates the angles of wearers' thighs.

FIG. 18 illustrates the pre-specified maximum positive thigh angle andpre-specified minimum negative thigh angle.

FIG. 19 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 20 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 21 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 22 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 23 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 24 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 25 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 26 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

FIG. 27 illustrates an embodiment of an orthotic exoskeleton comprisingan embodiment of a robotic joint.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the presented concepts. Thepresented concepts may be practiced without some or any of thesespecific details. In other instances, well-known process operations havenot been described in detail so as not to obscure unnecessarily thedescribed concepts. While some concepts will be described in conjunctionwith the specific embodiments, it will be understood that theseembodiments are not intended to be limiting.

FIG. 1 shows an embodiment of energetically passive robotic joint 100.Robotic joint 100 comprises first link 102, middle link 104, torquegenerator 108, second link 110, and locking mechanism 112. Middle link104 is rotatably coupled to first link 102 from its first end 131 wherefirst joint 106 represents the rotation of middle link 104 relative tofirst link 102. Torque generator 108 is capable of producing torquebetween first link 102 and middle link 104. Second link 110 is rotatablycoupled to second end 133 of middle link 104 where second joint 114represents the rotation of middle link 104 relative to second link 110.Locking mechanism 112 is capable of impeding the rotational motion ofsecond link 110 with respect to middle link 104 when second link 110 isflexing relative to middle link 104. In other words, when lockingmechanism 112 is in its locking state, angle 154 cannot get smallereasily and, in the limit, depending on the nature of locking mechanism112, angle 154 cannot get smaller at all. In an embodiment of thedisclosure, when locking mechanism 112 is in its locking state, angle154 cannot get smaller easily and, in the limit, depending on the natureof locking mechanism 112, angle 154 cannot get smaller at all, but canalways get larger. In other words, in some embodiments of thedisclosure, when locking mechanism 112 is in its locking state, middlelink 104 and second link 110 get locked to each other such that angle154 does not get smaller but can always get larger. When lockingmechanism 112 is in its unlocking state, middle link 104 and second link110 can always rotate relative to each other and angle 154 can alwaysget larger or smaller.

For better understanding of the concept of FIG. 1, assume first link 102is the thigh link and second link 110 is the shank link of anexoskeleton orthotic system. Further assume middle link 104 has a veryshort length. First direction 111 and second direction 113 represent therotational motion of second link 110 relative to first link 102. Adecrease in angle 153 or a decrease in angle 154 results in rotation ofsecond link 110 relative to first link 102 in first direction 111. Anincrease in angle 153 or an increase in angle 154 results in rotation ofsecond link 110 relative to first link 102 along second direction 113.Middle link 104 and first link 102 are flexing relative to each other,when angle 153 is getting smaller. When angle 153 is getting larger,middle link 104 and first link 102 are extending relative to each other.When angle 154 is getting smaller, second link 110 and middle link 104are flexing relative to each other. When angle 154 is getting larger,second link 110 and middle link 104 are extending relative to eachother. When second link 110 is moving along first direction 111, we meansecond link 110 is flexing relative to first link 102. When second link110 is moving along second direction 113, we mean second link 110 isextending relative to first link 102. Thus, in some embodiments, in thelocking state, locking mechanism 112 is configured to impede therotation of second link 110 relative to first link 102 in first rotationdirection 111. In some embodiments, in the unlocking state, lockingmechanism 112 allows free rotation of the second link 110 relative tofirst link 102 in first direction 111 and second direction 113. “Freerotation” is defined as motion only impeded by residual friction forces.

In some embodiments, second link 110 can always extend relative tomiddle link 104 along second direction 113 regardless of the state oflocking mechanism 112. This means angle 154 can always become largerregardless of the state of the locking mechanism 112. However, lockingmechanism 112 can impede only the flexion motion of second link 110relative to middle link 104 when locking mechanism 112 is in its lockingstate. This means locking mechanism 112 can substantially impede angle154 to become smaller when locking mechanism 112 is in its lockingstate. The level of this impedance to flexion of the locking mechanism112 may vary. In some embodiments of the disclosure, locking mechanism112 can totally lock second link 110 and middle link 104 to prevent therotational flexion of second link 110 relative to middle link 104, whenlocking mechanism 112 is in its locking state. However, second link 110and middle link 104 can extend relative to each other regardless iflocking mechanism 112 is in locking state or unlocking state. Theembodiment shown in FIG. 1 has novel properties which are describedbelow.

In the preferred embodiment, in operation when locking mechanism 112 isin its locking state, second link 110 gets locked to middle link 104. Inthis case second link 110 and middle link 104 act as one rigid body andcannot flex relative to each other. However, both middle link 104 andsecond link 110 can extend relative to each other at all times. Oncelocking mechanism 112 prevents the flexion of second link 110 and middlelink 104 relative to each other, rotational motion of middle link 104and second link 110 taken as a whole relative to first link 102 isresisted by torque generator 108 along first direction 111. In otherwords, middle link 104 and second link 110, taken together, is not freeto flex relative to first link 102 along first direction 111. However,second link 110 is free to rotate along second direction 113 (i.e.second link 110 can extend relative to first link 102 at all times.)When locking mechanism 112 is in an unlocked state, second link 110rotates freely relative to first link 102 along both directions shown byfirst direction 111 and second direction 113. That is, the embodimentdescribed here allows for either free motion or resisted motion ofsecond link 110 relative to first link 102 along first direction 111depending on the state of the locking mechanism 112. When the lockingmechanism 112 is in a locking state, torque generator 108 providesresistance to flexion motion between first link 102 and second link 110however unimpeded motion is always allowed between first link 102 andsecond link 110. When locking mechanism 112 is unlocked state, therewill be no resistance in flexion and extension motion between first link102 and second link 110. The importance of this is further describedbelow.

In some embodiments of the disclosure, the axis of rotation of firstlink 102 relative to middle link 104 and the axis of rotation of secondlink 110 relative to middle link 104 are substantially parallel to eachother. In some embodiments of the disclosure, the axis of rotation offirst link 102 relative to middle link 104 and the axis of rotation ofsecond link 110 relative to middle link 104 coincide on each other. Thisleads to a zero length for middle link 104. FIG. 2 shows an embodimentof robotic joint 500 where middle link 104 has a zero length. Since thelength of middle link 104 is shortened to zero, both joints 106 and 114coincide with each other. This architecture is of particular importancesince it leads to a smaller robotic joint. The embodiment shown in FIG.2 has a great application as the knee joint of an exoskeleton orthoticleg that is worn by a person. This is shown in FIG. 3 where roboticjoint 500 is worn on the person lower limb 502. When locking mechanism112 is in locking state, middle link 104 gets locked to second link 110.This causes the rotation of second link 110 relative to first link 102to be impeded by torque generator 108 along first direction 111.However, second link 110 and first link 102 can extend relative to eachother because second link 110 and middle link 104 are free to extend atall times (locking mechanism 112 locks second link 110 and middle link104 together only when they flex relative to each other). Thisrepresents the stance phase for robotic joint 500 where the motion ofsecond link 110 (coupled to person's shank 182) relative to first link102 (coupled to person's thigh 180) is impeded during knee flexion, butis free to extend. When locking mechanism 112 is in unlocking state, therotation of second link 110 relative to first link 102 is free in bothdirections 111 and 113. This represents the swing phase for roboticjoint 500 where person's shank 182 is free to move relative to person'sthigh 180 in both flexion and extension rotations. In summary, therobotic joint shown in FIG. 3 is able to successfully duplicate theproperties that are needed for an orthotic or a prosthetic leg. Justbefore the stance phase is over, locking mechanism 112 unlocks middlelink 104 from second link 110. This causes free motion of second link110 relative to middle link 104 for flexion and extension needed duringthe swing phase. Just before the leg strikes the ground, lockingmechanism 112 moves to locking state where second link 110 cannot movetoward middle link 104 anymore (i.e. second link 110 cannot flexrelative middle link 104.) When locking mechanism 112 is in its lockingstate, the extension of second link 110 relative to middle link 104 ispossible. This means the person wearing robotic joint 500 can alwaysextend regardless of status of locking mechanism 112.

As shown in FIG. 3, in some embodiments of the disclosure, first link102 is configurable to move in unison with person's thigh 180 and secondlink 110 is configurable to move in unison with person's shank 182. Insome embodiments of the disclosure, first link 102 is configurable to becoupled to person's thigh 180 and second link 110 is configurable to becoupled to person's shank 182. As described below various braces can beused to allow for this coupling. One can use robotic joint 500 inreverse position; this means in some embodiments of the disclosure,first link 102 is configurable to move in unison with person's shank 182and second link 110 is configurable to move in unison with person'sthigh 180. In some embodiments of the disclosure, first link 102 isconfigurable to be coupled to person's shank 182 and second link 110 isconfigurable to be coupled to said person's thigh 180. Various bracescan be used to allow for this coupling. In some embodiments, thesebraces may take the form of straps, rigid connections, semi-rigidconnections or combinations of these elements.

In some embodiments of the disclosure, torque generator 108 may producea passive resistive torque between first link 102 and middle link 104.In these embodiments of the disclosure, torque generator 108 does notrequire any external energy source to deliver movement. In this case,one can imagine torque generator 108 as a simple spring that resistsexternal flexion torques (e.g. torque imposed by the wearer) thatattempt to flex first link 102 and middle link 104 relative to each. Inthese embodiments, torque generator 108 represents the general mechanismthat generates passive resistive torques. Examples of the torquegenerator 108 include without limitation a pneumatic or hydrauliccylinder or a cylinder with hydraulic and pneumatic components, gassprings, hydraulic dampers, lockable gas springs, and lockable dampers.In some embodiments of the disclosure, the torque generator 108 iscapable of locking, such that the locked torque generator resists allmotion of the first link 102 relative to the middle link 104. In theseembodiments, an actuator can be present to unlock the torque generator.In some embodiments of the disclosure, the actuator for the lockabletorque generator 108 comprises an element or combination of elementsselected from a group consisting of electric motors, electric motorswith transmission, solenoids, hydraulic actuators, and pneumaticactuators.

In some embodiments of the disclosure, torque generator 108 is an activeelement that can produce arbitrary torque between first link 102 andmiddle link 104. In this case, one can imagine torque generator 108 asan actuator that provides flexion and extension torques between firstlink 102 and middle link 104 regardless of external torques. In theseembodiments of the disclosure, electric motors and actuators are used toprovide controllable torque at the torque generator 108. This allows thetorque profile of torque generator 108 to be customized for varioustasks. For instance, walking and stair ascent require different torqueprofiles at the person's knee.

FIG. 4 shows an embodiment of robotic joint 500 which is designed basedon the operation of embodiments described above and depicted in FIG. 1,FIG. 2, and FIG. 3. FIG. 5 shows an exploded view of robotic joint 500shown in FIG. 4. In this embodiment, first joint 106 and second joint114 coincide on each other and therefore middle link 104 has zerolength. With the help of FIGS. 4 through 8, robotic joint 500 isdescribed below. The embodiment of robotic joint 500 comprises a firstlink 102 and a middle link 104 which is rotatably coupled to first link102. Middle link 104 has zero length whereas the length is the distancebetween joint 106 and second joint 114, as shown in FIG. 5. Roboticjoint 500 further comprises a torque generator 108 which is capable ofproducing a resistive torque between first link 102 and middle link 104.Middle link 104, as shown in FIG. 5, comprises an arm 155 and arbor 109.Torque generator 108 is rotatably coupled to arm 155 (a component ofmiddle link 104) from its first end 57. Torque generator 108 isrotatably coupled to first link 102 from its second end 59. In someembodiments of the disclosure, torque generator 108 is a gas spring. Insome embodiments of the disclosure, torque generator 108 is acompression coil spring. In some embodiments of the disclosure, firstlink 102 comprises a clevis 159 (shown in FIG. 7 and FIG. 8). Clevis 159can be manufactured as a part of first link 102. The second end oftorque generator 108 (shown by 59) is rotatably coupled to first link102 at clevis 159. FIG. 5 also shows controller 120 on circuit board 129and battery 127.

Robotic joint 500 further comprises a second link 110 which is rotatablycoupled to middle link 104. In some embodiments of the disclosure,second link 110 comprises a main shaft 156. The coupling between secondlink 110 and disk 118 is achieved by interfacing a non-circular maleboss 152 (shown in FIG. 6) on main shaft 156 to a correspondingnon-circular female cutout 151 on disk 118 and a fastener (not shown)through hole 157. Disk 118 in FIG. 6 is shown as a section view forclarity. According to this architecture, as shown in FIG. 6, disk 118and second link 110 are coupled to each other and rotate at the samespeed.

In the absence of torque generator 108 and locking mechanism 112, firstlink 102, second link 110 and middle link 104 rotate independently alongaxis 145 of main shaft 156. A fastener (not shown in FIG. 7) throughhole 157 retains the assembly containing second link 110, first link 102and middle link 104 together. Also, note that all rotating bearingsamong these joints are eliminated for clarity. An ordinary skilled inthe art would understand that there must be bearing surfaces (e.g., ballbearings, or roller bearings) between second link 110, middle link 104,and first link 102 for smooth rotational motion.

Locking mechanism 112, shown in FIG. 8 comprises wrap spring 117, disk118, and actuator 115. First end 158 of wrap spring 117 is coupled tosecond link 110. This coupling can be accomplished by a variety ofmechanical methods; however, an embodiment of this coupling is describedbelow with the help of FIG. 8. The coupling of the wrap spring 117 tosecond link 110 is facilitated by using disk 118 and clamp 116. Firstend 158 of the warp spring 117 is mounted around disk 118. Clamp 116clamps first end 158 of wrap spring 117 to disk 118. In some embodimentsof the disclosure, clamp 116 may clamp one or more coils of the wrapspring 117 to disk 118. As described above and shown in FIG. 7, disk 118and second link 110 are coupled to each other and rotate at the samespeed. The coupling between second link 110 and disk 118 is achieved byinterfacing a non-circular male boss 152 (shown in FIG. 6) on secondlink 110 to a corresponding non-circular female cutout 151 on disk 118and a fastener (not shown) through hole 157. The second end 119 of wrapspring 117 is wrapped around the cylindrical surface of arbor 109 ofmiddle link 104 such that the cylindrical surface of arbor 109 islocated substantially inside wrap spring 117 with its major axissubstantially parallel to the major axis 145 of wrap spring 117. Lockingmechanism 112 further comprises an actuator 115 which is coupled tosecond link 110. Actuator 115 is capable of moving the second end 119 ofthe wrap spring 117 to provide pressure between the cylindrical surfaceof arbor 109 of middle link 104 and an inner surface 150 of wrap spring117. This pressure causes a resistive torque between the cylindricalsurface of arbor 109 and wrap spring 117. Consequently, the resistivetorque between middle link 104 and second link 110 can be controlled bycontrolling the second end 119 of wrap spring 117. Note that disk 118 iscoupled to second link 110 (they rotate together) and first end of wrapspring 117 is coupled to disk 118. As the second end 119 moves with thehelp of actuator 115 along arrow 146 (FIG. 9), the resistive torquebetween middle link 104 and second link 110 increases. As second end 119moves with the help of actuator 115 along arrow 147 (FIG. 11), theresistive torque between middle link 104 and second link 110 decreasessubstantially.

FIG. 9 and FIG. 10 show an embodiment of the disclosure where torquegenerator 108 takes the form of a gas spring. If actuator 115 moves thesecond end 119 along arrow 146, locking mechanism 112 is in the lockingstate. In this locking state, second link 110 and middle link 104 arelocked to each other and cannot flex relative to each other. In thisstate, the motion of second link 110 relative to first link 102 alongfirst direction 111 occurs by compressing the gas spring torquegenerator 108. The compression of torque generator 108 is seen in FIG.10. In other words, when actuator 115 moves second end 119 along arrow146, there will be resistance for flexion of first link 102 and secondlink 110 relative to each other. However, first link 102 and second link110 are free to extend relative to each other at all times even whensecond end 119 has been moved along arrow 146. If actuator 115 moves thesecond end 119 along arrow 147, as shown in FIG. 11 and FIG. 12, lockingmechanism 112 is in an unlocking state. In this state, the motion ofsecond link 110 relative to first link 102 along first direction 111occurs sustainably without impedance (no gas spring compression). Inother words, when actuator 115 moves second end 119 along arrow 147,there will be no resistance for flexion of first link 102 and secondlink 110 relative to each other. In this situation, first link 102 andsecond link 110 are always free to extend relative to each other.

In some embodiments of the disclosure, actuator 115 comprises an elementor combination of elements selected from a group consisting of electricmotors, electric motors with transmission, solenoids, hydraulicactuators, pneumatic actuators and passive mechanical mechanisms.

Locking mechanism 112 represents the general mechanism that impeded themotion between the middle link 104 and the second link 110 when thelocking mechanism 112 is in the locking state. In the embodiment of FIG.8, locking mechanism 112 uses a wrap spring 117 and an arbor 109. Inthis embodiment, locking mechanism 112 is configured to impede therotation of the second link 110 relative to the middle link 104 by useof the friction force between two surfaces. In this embodiment of thedisclosure, where wrap spring 117 is used, in locking mechanism 112, asmall actuator 115 can be employed to change the state of the lockingmechanism 112. An ordinary skilled in the art would recognize that thereare other methods of employing friction forces between surfaces toprovide the intended function of locking mechanism 112. Examples oflocking mechanism 112 include without limitation caliper brakes, diskbrakes, band brake, ratchet and pawl assembly, linkage assembliesincluding bi-stable linkage assemblies.

FIG. 13 shows an embodiment of the disclosure where robotic joint 500 iscoupled to a person's knee where first link 102 is coupled to a person'sthigh 180 and second link 110 is coupled to person's shank 182. Firstdirection 111 represents the knee flexion motion and second direction113 is the knee extension motion. The person's knee joint issubstantially coincident with the single axis of rotation 145 of roboticjoint 500.

As shown in FIG. 13, in some embodiments of the disclosure, roboticjoint 500 is coupled to a person's knee where first link 102 isconfigured to move in unison with person's thigh 180 and second link 110is configured to move in unison with said person's shank 182. In someembodiments of the disclosure, robotic joint 500 further comprises athigh connector 132 that allows coupling to a person's thigh 180. Insome embodiments of the disclosure, robotic joint 500 further comprisesa shank connector 134 that allows coupling to a person's shank 182. Insome embodiments of the disclosures thigh connector 132 and shankconnector 134 comprise braces. Although braces have been used todemonstrate the coupling of first link 102 and second link 110 to theperson's thigh 180 and shank 182 in FIG. 13, an ordinary person skilledin the art would understand that many methods and devices can beemployed that would cause second link 110 and first link 102 to move inunison with person's shank 182 and person's thigh 180. Coupling throughshank braces and thigh braces is only one method of causing the unisonmovement of first link 102 with person's thigh 180 and second link 110with wearer's shank 182.

FIG. 14 shows an embodiment where robotic joint 500 is employed in amanner mirrored to how it is used in FIG. 13. FIG. 14 shows anembodiment of the disclosure where robotic joint 500 is coupled to aperson's knee where first link 102 is coupled to a person's shank 182and second link 110 is coupled to the person's thigh 180. In someembodiments of the disclosure, robotic joint 500 is coupled to aperson's knee where first link 102 is configured to move in unison withperson's shank 182 and said second link 110 is configured to move inunison with said person's thigh 180 wherein first direction 111 is theknee flexion direction and second direction 113 is the knee extensiondirection. An ordinary person skilled in the art can see that mirroringthe orientation of the embodiment in FIG. 13 produces the embodiment inFIG. 14. Thus, all description, which refers to the orientation of theembodiment shown in FIG. 13, can be applied to the orientation shown inFIG. 14.

FIG. 15 shows an embodiment of robotic joint 500, which is configured tobe coupled to the lower extremity of a person. Robotic joint 500 furthercomprises a controller 120 (shown in FIG. 5) and at least one leg sensor123 capable of producing a leg signal 121. Leg signal 121 is used bycontroller 120 to control the locking and unlocking states of lockingmechanism 112. Examples of leg sensor 123 include, without limitation,rotary potentiometers, linear potentiometers, magnetic encoders, opticalencoders, linear variable differential transformers, capacitivedisplacement sensors, eddy current proximity sensors,variable-inductance proximity sensors, rocker switches, slide switches,accelerometer, inertial measurement units, gyroscopes and combinationsthereof.

Examples of leg signal 121 include, without limitation, a signalrepresenting the absolute angle of the link coupled to person's thigh180, which in some embodiments is first link 102 and in otherembodiments is second link 110, relative to vertical gravitational line140 or ground 144, a signal representing the velocity of the linkcoupled to person's thigh 180 relative to ground 144 or gravitationalline 140, a signal representing the velocity of the link coupled toperson's thigh 180, a signal representing the acceleration of linkcoupled to person's thigh 180 relative to ground 144 or gravitationalline 140, a signal representing the angle between the person's torso 181(person's torso is shown in FIG. 21) and the link coupled to the thigh180, a signal representing the speed of the link coupled to the thigh180 relative to the person's torso 181, a signal representing theacceleration of the link coupled to the thigh 180 relative to person'storso 181 and combinations thereof. In some embodiments of thedisclosure, controller 120 is coupled to first link 102. In someembodiments of the disclosure, controller 120 is coupled to second link110. In an embodiment of robotic joint 500, leg signal 121 is a signalthat represents the absolute angle of first link 102 relative tovertical gravitational line 140 as shown in FIG. 15. In someembodiments, leg signal 121 indicates that the absolute angle ofperson's thigh 180 with respect to a line selected from the groupconsisting of vertical gravitational line 140 and a line substantiallyparallel with a person's torso. In some embodiments, leg signal 121indicates that the absolute angle of one of first link 102 or secondlink 110, which is coupled to the person's thigh 180 with respect to aline selected from the group consisting of a vertical gravitational line140 and a line substantially parallel with a person's torso.

Vertical gravitational line 140 is parallel to gravitational force. Inthe embodiment of FIG. 15, an inertial measurement unit (IMU) sensor canbe secured to the person's thigh 180 and generates the absolute angle ofthe person's thigh 180 or the link coupled to the thigh (first link 102in the embodiment shown in FIG. 13 or second link 110 shown in FIG. 14)with respect to vertical gravitational line 140. Since the person'sthigh 180 and first link 102 move in unison with each other, then legsensor 123 can be secured to either the person's thigh 180 or to firstlink 102.

FIG. 16 is a schematic illustration of controller finite state machine700 having two primary states, in accordance with some embodiments.These states may include locking state 200 and unlocking state 201.Unlocking state 201 represents the state where locking mechanism 112 isin its unlocking state and first link 102 and second link 110 are freeduring both extension and flexion relative to each other. Locking state200 represents the state where locking mechanism 112 is in its lockingstate where the flexion of first link 102 and second link 110 is impededby torque generator 108.

In some embodiments, controller 120 may initially be in locking state200. In locking state 200, controller 120 may enter unlocking state 201if leg signal 121 is represented by, negative thigh angle 143 (FIG. 17),which is a signal representing the absolute angle of the person's thighor the link coupled to person's thigh 180, (either first link 102 orsecond link 110), relative to vertical gravitational line 140, issmaller than a predefined minimum negative thigh angle 166. Predefinedminimum negative thigh angle 166 is shown in FIG. 18. This means ifrobotic joint 500 is in its locking state (i.e., locking mechanism 112is in its locking state), and if the measurement of the negative thighangle 143 becomes smaller than the predefined minimum negative thighangle 166, then finite state machine 700 will move to unlocking state201. In this case, locking mechanism 112 moves into its unlocking state201 and allows second link 110 to freely flex and extend relative tofirst link 102.

In some embodiments, when controller 120 is in unlocking state 201,controller 120 will enter locking state 200 if leg signal 121,represented by positive thigh angle 142 (FIG. 17), becomes larger thanpredetermined maximum positive thigh angle 165. Predetermined maximumpositive thigh angle 165 is shown in FIG. 18. This means when the wearerleg is in the swing phase and the positive thigh angle from vertical 142becomes larger than predetermined maximum positive thigh angle 165,locking mechanism 112 will move into locking state 200. In thissituation, robotic joint 500 of FIG. 15 can freely extend, but torquegenerator 108 will provide resistance for flexion of first link 102 andsecond link 110 relative to each other. This resistance prevents roboticjoint 500 from collapsing and supports the wearer's leg during thestance phase of the walking.

The controller can move to unlocking state 201 and locking state 200 asa result of external inputs also, which may be different from leg signal121 generated by leg sensor 123.

In some embodiments, robotic joint 100 or 500 comprises manual lockingdevice 208 as, for example, shown in FIG. 13. Manual locking device 208is configured to generate locking signal 206 for controller 120. Whenmanual locking device 208 is activated during operation and controller120 receives locking signal 206, finite state controller moves intolocking state 200. As noted above, in locking state 200, lockingmechanism 112 is in its locking state, and the flexion motion of firstlink 102 and second link 110 is resisted by torque generator 108. Inthis case, the extension motion of first link 102 relative to secondlink 110 is free and unimpeded. In some embodiments of the disclosure,depending on the nature of the torque generator 108, the extensionmotion of first link 102 relative to second link 110 may be assisted.

In some embodiments, robotic joint 100 or 500 comprises manual unlockingdevice 209 as, for example, shown in FIG. 13. Manual unlocking device209 is configured to generate manual unlocking signal 203 for controller120. When manual unlocking device 209 is activated and controller 120receives manual unlocking signal 203, robotic joint 100 or 500 movesinto unlocking state 201. In unlocking state 201, locking mechanism 112is in its unlocking state and first link 102 and second link 110 arefree to flex and extend relative to each other.

In some embodiments of the disclosure, robotic joint 100 or 500comprises manual sitting device 207. Manual sitting device 207 isconfigured to generate sitting signal 205 for controller 120. Inoperation, when sitting device 207 is activated and controller 120receives sitting signal 205, robotic joint 100 or will move intounlocking state 201. This allows the wearer to comfortably sit on achair without any resistance.

In some embodiments, as shown in FIG. 15, predetermined minimum negativethigh angle 166 and predetermined maximum positive thigh angle 165 areassigned to the controller 120 using a user interface 126. In someembodiments, user interface 126 is configured to display leg signal 121.In some embodiments, user interface 126 comprises any signal generatorsuch as without limitation push buttons, switch, momentary switch,sliding switch, a knob, potentiometers, encoders, or combinationsthereof. In some embodiments, the user interface 126 may comprise agraphical wearer interface. Some examples of graphical wearer interface126 include, without limitation, a mobile phone, a tablet, a laptop, adesktop, a monitor, and combinations thereof. User interface 126 isconfigured to produce locking signal 206, unlocking signal 203, andsitting signal 205 and to transmit the signals (and other information)to controller 120.

Locking signal 206 is capable of moving the controller from any state toits locking state 200. Unlocking signal 203 is capable of moving thecontroller 120 from any state to the unlocking state 201. Sitting signal205 is capable of moving the controller 120 from any state to thelocking state 200. In some embodiments, the user interface 126communicated with the controller 120 wirelessly via a wireless protocol.In some embodiments, the user interface 126 communicates with thecontroller 120 over wires.

Robotic joint 100 or 500 can be used in a variety of configurations.FIG. 19 shows an embodiment of an exoskeleton 300 which comprisesrobotic joint 500. In the embodiment shown in FIG. 19, first link 102 iscoupled to a person's thigh 180 and second link 110 is coupled toperson's shank 182. The person's knee joint is substantially alignedwith a single axis of rotation 145. Second link 110 extends towards theground and is coupled to foot link 103 such that foot link 103 canrotate relative to second link 110 about ankle joint 101. In someembodiments of the disclosure, foot link 103 is coupled to person's foot183. Foot link 103 is coupled to the wearer to move in unison withperson's foot 183 by using various forms of strapping and bracing. Insome embodiments of the disclosure, foot link 103 is embedded into shoe184. In some embodiments of the disclosure, foot link 103 is wornoutside the wearer's shoes. In some embodiments of the disclosure, footlink 103 is worn inside the wearer's shoes.

In some embodiments of the disclosure, such as the embodiment shown inFIG. 19, exoskeleton 300 comprises robotic joint 500 and an ankleexoskeleton 402 which is capable of being coupled to person's foot 183.In some embodiments of the disclosure, ankle exoskeleton 402 isconnectable to second link 110. In some embodiments of the disclosure,as shown in FIG. 19, ankle exoskeleton 402, is worn outside the wearer'sshoes 184.

FIGS. 20-22 depict embodiments of the disclosure wherein robotic joint500 can be used in a variety of configurations in conjunction withvarious ankle-foot orthoses.

In some embodiments of the disclosure, as shown in FIG. 20, exoskeleton400 comprises robotic joint 500 and ankle-foot-orthosis 404. In thisembodiment ankle-foot-orthosis 404 is worn inside the wearer's shoe likean insole (the wearer's shoes are not shown for clarity). An ordinaryperson skilled in the art can arrive at many forms of internal andexternal ankle-foot-orthoses that can be used in conjunction withrobotic joint 100 or 500.

FIG. 20 shows an embodiment of exoskeleton 400 where ankle-foot-orthosis404 is a standard solid ankle-foot-orthosis. This type ofankle-foot-orthosis stops plantarflexion and also stops or limitsdorsiflexion.

FIG. 21 shows an embodiment of exoskeleton 450 which comprises roboticjoint 500 and ankle-foot-orthosis 406, which is a standard short legankle-foot-orthosis (AFO) with a fixed (but sometimes adjustable) hinge.This type of AFO is relatively light and easy to fit into shoes. Anklefoot orthosis 406 comprises foot link 210.

FIG. 22 shows exoskeleton 600 comprising robotic joint 500 andankle-foot-orthosis 408, which is a Plantarflexion Stop AFO. This AFOacts to stop plantarflexion by not letting foot link 211 to pointdownwards. This type of AFO has an ankle joint 101 that allows fornormal dorsiflexion of the foot.

It should be appreciated that, although specific examples of differentankle-foot orthosis are shown, there are other types ofankle-foot-orthosis that could be utilized with the present disclosure.For example, in some embodiments of the disclosure, ankle-foot-orthosisis a Dorsiflexion Assist AFO (not shown). This type of AFO is similar tothe AFO shown in FIG. 21 but has a spring-like hinge that acts to raisethe foot link when the foot comes off the ground. In some embodiments ofthe disclosure, the ankle-foot-orthosis is a standard Posterior LeafSpring ankle-foot-orthosis. In some embodiments of the disclosure, theankle-foot-orthosis is an Energy Return ankle-foot-orthosis. This typeof AFO uses a natural flex built into the material of the AFO to provideassistance in dorsiflexion. These devices are often made of carbongraphite materials. In general, the ankle-foot-orthosis of the presentdisclosure comprises any device or combination of internal or externalankle-foot-orthosis capable of performing the indicated functions.Examples of external or internal ankle-foot-orthosis include, withoutlimitation, flexible AFO, rigid AFO, AFO with tamarack flexure, AFO withanti-talus, AFO anti-talus (anterior shell or shell in the front), AFOwith a free-motion ankle joint, AFO with an adjustable rigid anklejoint, AFO with a spring-loaded ankle joint, AFO with an adjustablespring-loaded ankle joint and combinations thereof.

FIG. 23 shows an embodiment of the disclosure where exoskeleton 610further comprises an exoskeleton trunk 350. Exoskeleton trunk 350 isconfigurable to be coupled to the person's upper body 181. In someembodiments of the disclosure, exoskeleton trunk 350 couples torso link130 coupled to the person's upper body 181 using a torso connection 353.In some embodiments of the disclosure, exoskeleton trunk 350 is coupledto a person like a backpack (not shown). In some embodiments of thedisclosure, exoskeleton trunk 350 is coupled to a person like a belt, asdepicted in FIG. 23, for example. Exoskeleton trunk 350 comprises atorso link 130 capable of being coupled to a person's upper body andtorso. Exoskeleton trunk 350 further comprises thigh link 107 configuredto be coupled to the person's thigh 180. Thigh link 107 is coupled tomove in unison with the person's thigh 180. In some embodiments, thighlink 107 of exoskeleton trunk 350 is coupled to first link 102 ofrobotic joint 500. In some embodiments thigh link 107 of exoskeletontrunk 350 is coupled to second link 110 of robotic joint 500. In someembodiments of the disclosure exoskeleton trunk 350 and robotic joint500 are not coupled together. Exoskeleton trunk 350 further comprises atrunk thigh link 351 configurable to rotatably couple thigh link 107 totorso link 130. In some embodiments of the disclosure, trunk thigh link351 is coupled to thigh link 107. In some embodiments of the disclosure,trunk thigh link 351 is not coupled to thigh link 107. In an alternativeembodiment not shown, trunk thigh link 351 is coupled to person's thigh180. In some embodiments of the disclosure, exoskeleton trunk 350further comprises an actuator 358 capable of providing torque betweentorso link 130 and trunk thigh link 351. Axis 352 is the hip flexionextension axis. The controller box 367 and the batteries 369 for theactuators are shown in FIG. 23. In some embodiments of the disclosure,leg signal 121 represents the absolute angle of first link 102 relativeto a vertical gravitational line 140 or relative to ground 144. In someembodiments of the disclosure, leg signal 121 represents the absoluteangle of trunk thigh link 351 relative to a vertical gravitational line140 or relative to ground 144 (not shown). In some embodiments of thedisclosure, leg signal 121 represents the angle of trunk thigh link 351with respect to torso link 130 which is substantially parallel with theperson's torso.

FIGS. 24-27 depict embodiments of the present disclosure (exoskeletons620, 630, 640, and 650) including both an exoskeleton trunk 350 and anankle exoskeleton or ankle-foot orthosis (e.g., 402, 404, 406, and 408).In the embodiments shown, the ankle-foot orthosis of the presentdisclosure (404, 406, 408) is capable of being coupled to person's foot183 and is connectable to a link coupled to the shank 182 such as thesecond link 114. The embodiment of FIG. 24, exoskeleton trunk 350 iscoupled to a person with shoulder straps 188.

What is claimed is:
 1. A robotic exoskeleton joint configured to becoupled to a lower extremity of a person, the robotic exoskeleton jointcomprising: a first link; a middle link, comprising a first end and asecond end, wherein the first end of the middle link is rotatablycoupled to the first link at a first joint; a torque generator,configured to produce a torque between the first link and the middlelink; a second link, rotatably coupled to the second end of the middlelink at a second joint; and a locking mechanism, switchable between alocking state and an unlocking state independent of the torque of thetorque generator, wherein: the locking mechanism, in the locking state,prevents flexion of the second link and the middle link relative to eachother, the locking mechanism, in the unlocking state, allows freeflexion and extension of the second link and the middle link relative toeach other, and when the locking mechanism is in the locking state andthereby prevents the flexion of the second link and the middle linkrelative to each other, the torque generator impedes flexion of thesecond link and the first link about a first joint by applying torque tothe middle link.
 2. The robotic exoskeleton joint of claim 1, wherein anaxis of rotation of the first link relative to the middle link and anaxis of rotation of the second link relative to the middle link coincidewith each other.
 3. The robotic exoskeleton joint of claim 1, wherein anaxis of rotation of the first link relative to the middle link and anaxis of rotation of the second link relative to the middle link aresubstantially parallel to each other.
 4. The robotic exoskeleton jointof claim 1 further comprising an actuator, wherein the locking mechanismlocks the middle link to the second link by the actuator.
 5. The roboticexoskeleton joint of claim 4, wherein the actuator comprises an elementor a combination of elements selected from the group consisting of anelectric motor, an electric motor with a transmission, a solenoid, ahydraulic actuator, and a pneumatic actuator.
 6. The robotic exoskeletonjoint of claim 1, wherein the torque generator is selected from thegroup consisting of a pneumatic cylinder, a hydraulic cylinder, acylinder with a hydraulic component, a cylinder with a pneumaticcomponent, a gas spring, an air spring, a hydraulic damper, a lockablegas spring, a lockable damper, a compression spring, a tensile spring, acoil spring, an electric motor, an electric motors with a transmission,a solenoid, a hydraulic actuator, and a pneumatic actuator.
 7. Therobotic exoskeleton joint of claim 1, wherein one of the first link andthe second link is configurable to be coupled to a thigh of a person,and wherein another one of the first link and the second link isconfigurable to be coupled to a shank of the person.
 8. The roboticexoskeleton joint of claim 1, wherein one of the first link and thesecond link is configurable to move in unison with a thigh of a person,wherein another one of the first link and the second link isconfigurable to move in unison a shank of the person.
 9. The roboticexoskeleton joint of claim 1 further comprising at least one controllerconfigured to move the locking mechanism to the locking state justbefore a leg of the person strikes a ground.
 10. The robotic exoskeletonjoint of claim 1, further comprising at least one controller configuredto move the locking mechanism to the unlocking state just before astance phase is over.
 11. The robotic exoskeleton joint of claim 1,further comprising at least one controller operable to receive at leastone leg signal from the robotic exoskeleton joint, wherein thecontroller is configured to move the locking mechanism to the lockingstate based on the at least one leg signal.
 12. The robotic exoskeletonjoint of claim 11, wherein the at least one signal represents anabsolute angle of one of the first link or the second link, which isconfigured to be coupled to a thigh of the person, with respect to aline selected from the group consisting of a vertical gravitational lineand a line substantially parallel with a torso of a person.
 13. Therobotic exoskeleton joint of claim 11, wherein the at least one signalrepresents an absolute angle of a thigh of a person with respect to aline selected from the group consisting of a vertical gravitational lineand a line substantially parallel with a torso of the person.
 14. Therobotic exoskeleton joint of claim 11, wherein the at least onecontroller is configured to move the locking mechanism to the lockingstate when the at least one leg signal indicates that an absolute angleof a thigh of the person with respect to a line selected from the groupconsisting of a vertical gravitational line and a line substantiallyparallel with a torso of the person is larger than a pre-specifiedmaximum positive thigh angle.
 15. The robotic exoskeleton joint of claim11, wherein the at least one controller is configured to move thelocking mechanism into an unlocking state when the at least one legsignal indicates that an absolute angle of a thigh of the person withrespect to a line selected from the group consisting of a verticalgravitational line and a line substantially parallel with a torso of theperson is smaller than a pre-specified minimum negative thigh angle. 16.The robotic exoskeleton joint of claim 11, wherein the at least onecontroller is configured to move the locking mechanism to the lockingstate when the at least one leg signal indicates that an absolute angleof one of the first link or the second link, which is configured to becoupled to a thigh of the person with respect to a line selected fromthe group consisting of a vertical gravitational line and a linesubstantially parallel with a torso of the person is larger than apre-specified maximum positive thigh angle.
 17. The robotic exoskeletonjoint of claim 11, wherein the at least one controller is configured tomove the locking mechanism into the unlocking state when the at leastone leg signal indicates that an absolute angle of one of the first linkor the second link, which is configured to be coupled to a thigh of aperson, with respect to a line selected from the group consisting of avertical gravitational line and a line substantially parallel with atorso of the person is smaller than a pre-specified minimum negativethigh angle.
 18. The robotic exoskeleton joint of claim 11 furthercomprising a manual locking device operable to generate a manual lockingsignal for the at least one controller, wherein, when the manual lockingsignal is activated by the person, the locking mechanism moves into thelocking state.
 19. The robotic exoskeleton joint of claim 11, furthercomprising a manual unlocking device operable to generate a manualunlocking signal for the at least one controller, wherein, when themanual unlocking device is activated by a person, the locking mechanismmoves into the unlocking state.